Thanks Paolo! I saw the Aviation Week story and came directly here to see if anyone had a link to Yuichi Tsuda's paper and, as always, UMSF came through.

The sheer, simple elegance of this experimental spacecraft has always left me almost speechless. Integrating propulsion, power generation, attitude control, and science instrumentation into the sail was simply brilliant and a huge step beyond what any other solar sail experimental craft have been designed to do. I am so glad to see that JAXA and the IKAROS team have achieved all their goals and that so many of their concepts have been proven viable.

It is without a doubt the crowning achievement of JAXA to date IMO. It may well be the most important spacecraft of the last decade in terms of spacecraft propulsion and control. I look forward to their follow-on spacecraft that will build on this success and add an Ion engine.

if I understand correctly today's release, IKAROS has been put into hibernation owing to the large distance from the Earth and Sun, making communication difficult and owing to the quasi-depletion of its reserves of gas for attitude controlhttp://www.jspec.jaxa.jp/ikaros_channel/bn018.htmlpandaneko, can you confirm?

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I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

if I understand correctly today's release, IKAROS has been put into hibernation owing to the large distance from the Earth and Sun, making communication difficult and owing to the quasi-depletion of its reserves of gas for attitude controlhttp://www.jspec.jaxa.jp/ikaros_channel/bn018.htmlpandaneko, can you confirm?

Yes, Paolo, but not in one go、I am afraid. I will translate the whole lot in parts. First, the introduction.

Updated 6 January 2012.

About the result of reverse spin operation of IKAROS and transfer into heybernation mode

We have been analysing the result of above reverse spin operation carried out on 18 October 2011 and we are now able to offer detailed information about this reverse spinning.

Also, we are informing you that we have confirmed that IKAROS has entered into a hybernation mode, and this is judged from the operation records up until now, by 6 January 2012 (instruments shut down because of the decrease in the power generated).

◆ Result of the reverse spin operation

On 18 October 2011 IKAROS sfifted into the reverse spin status without any hitches. Its data is carried on the table 1 as follows.

if I understand correctly today's release, IKAROS has been put into hibernation owing to the large distance from the Earth and Sun, making communication difficult and owing to the quasi-depletion of its reserves of gas for attitude controlhttp://www.jspec.jaxa.jp/ikaros_channel/bn018.html

The rest of this release follows below.

◆ About the shitft into hibernation mode

Ikaros' behaviour after the reverse spin operation is now known to be like:

(2) IKAROS is currently flying on an elliptical orbit around the Sun, and its Solar distance in AU will continue to increase until March 2012 when it passes the furthest point from the Sun.

(3) Due to above (1), (2) a decrease in power is expected. As a result of this, if the generated power is less than the consumption power, then IKAROS will go into hibernation mode (i.e., shutting down instruments on board)

(4) Even if we tried the spin rate down operation (or, attitude control) by gas jet control our conclusion is that we will not be able to obtain dramatic changes as the remaining amount of fuel is so low.

（*1） Solar photon pressure priority mode:

IKAROS' attitude is strongly influenced by the Solar photons. Membrane is facing the Sun.

（*2） Inertially guided direction priority mode:

IKAROS' increasing spin rate is forcing IKAROS to take up the attitude (orientation) that is strongly influennced by this spin rate change. In the case of IKAROS, it is the increasing Sun angle.

Based on these behaviours we have not attempted any attitude control since early December and have simply continued to obtain the attitue data as the Sun angle increased, trying to check on the health of IKAROS.

Consequently, we are pleased to inform you that IKAROS has entered into hibernation mode by today.

From now on, we will try to investigate the possibility of signal reception once after the hibernation.

What follows is not a direct response to yours as above, but to another of yours that followd this. IKALOS operational status as in late April 2012 at ISAS(JAXA) operation room and that goes as follows:

However, IKALOS still seems to be in heybernation. Next operational contact is scheduled to be for 8 May.

I am KY from the team IKALOS. I offer my greetings from the team.

I am pleaased to say that thanks to your and all other people we have been able to finish the latter half of the operation ( from January 2011 to March 2012) without any hitches. I thank you profoundly for this. I really mean it.

We continued our dialogue with various sections within JAXA and I am pleased to say that now we will be able to continue with our operation of IKALOS from next fiscal year on. This is making it possible, if IKALOS comes back from its current heybernation, to monitor its membrane shape data and attitude control data. Our team is very pleased with this possibility.

Here's how Google does it, which in fact sounds like IKAROS has been heard from:

QUOTE

September 10, 2012 [update]Hibernation mode for the dawning of IKAROS

IKAROS is that you migrate to hibernation mode (shut down due to lower power generation onboard equipment) until January 6, Heisei 24 has been confirmed.Result after migration mode hibernation, has continued to explore the IKAROS paced operation twice a month, discovered radio waves looked like IKAROS on Thursday, September 06, Heisei 24, it is the IKAROS on Saturday 8 same I was confirmed.Thus, (restoration) that dawned from hibernation mode has been confirmed IKAROS.

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